114 



Fig. 58. Embryosac. X 265. After dissol- 

 ving of contents by means ofcbloral 

 hydrate. Showing 3 pairs of zygotes. 



Za and Za' belonging to pollen- 

 tube Px. 



Z/3 and Z|3' belonging to another 

 pollentube not visible in the section. 



Zy and Zy' belonging to a third 

 pollentube not visible in the section. 



The proembryomic tube of Zy' is 

 branching after having reached the 

 prothallium. This is usualy the case. 



T. 0. P. = Top of prothallium. 

 Fig. 59. Embryosac after formation of 

 the proembryo's. Showing relative 

 seize of fertil part of Embryosac and 

 of prothallium. The constriction of 

 the embryosac is now above the middle, 

 the prothallium is laterally extended. 

 X36. 



F. P. = Fertil part of Embryosac. 



C. 0. P. =: Coneshaped part of Pro- 

 thallium. 



Pr. = Prothallium. 

 Fig. 60. Upper part of embryosac of 

 fig. 59. X 150. 



Z. ^= Zygote sprouting in the 



usual way. 



Z. t. w. = Zygote whose sprouting 

 tube takes a wrong direction. 



P. 0. Z. w. i. U. d. b. Pr. = Proem- 

 bryonic tube of Zygote which is unvi- 

 sible disappearing behind prothallium. 



P. 0. Z. w. i. U. p. i. fr. o. P. =: idem 

 passing in front of prothallium. 



A. B. 0. Pr. T. =z Abnormal branch 

 of this proembryonic tube taking 

 wrong direction. 



R. P. C. 0. T. P. =: Retarded pro- 

 thalliumcells of fertil part. 



PLATE XI. 



Fig. 61. Old embryosac. X 80. 



A. and B. z= Proembryo's running 

 over the surface of coneshaped part , 

 cut off at both ends. 



C. Proembryo running over blue 

 surface of coneshaped part and at its 

 base penetrating into the prothallial 

 tissue. 



D. z=z Proembryo disappearing be- 

 hind prothallium. 



E. z=: Proembryo cutt off at both 

 sides before reaching the prothallium. 



Fig. 62. Archegoniumlike formation in 



top of prothallium. X 300. Longitu- 

 dinal section. 



Fig. 63. Surface view of archegonium- 

 like formation with proembryonic 

 tubes, which look like pollentubes 

 approaching it. X 300. 



Fig. 64. Tip of proembryonic tube during 

 sprouting of the seed. X I'^S. After 

 Bower. 



Fig. 65. Idem, younger stage. X 175. 

 After Bower. For explanation of 

 the two latter figures see historical 

 part. 



